A Natural Farming System For Sustainable Agriculture In the Tropics Sustainable Agriculture Book - Chapter 9 Companion Planting
Companion planting is Fundamental #3. It is also called inter cropping. These crops are used for insect control, to make wind blocks, and they promote soil conservation. When harvested, they are used for compost and feed for livestock. Companion plants also create a desirable mulch and green fertilizer. Under sowing is a very popular means of companion planting also.
Some plants give benefits that help others grow. Tomatoes do well with carrots because the carrots stimulate the growth of tomatoes. Others, like marigold, ward off certain insects. Onions prevent the carrot fly from infesting the root with eggs. Papaya wards off corn pests.